ATTORNEY I' UNITED-f My invention relates to shearing, devices and more particularly to those of the vrotary type wherein a cutter is rotatably mounted within a guard and has for its principal object to provide a more elcient cutter construction. that retains use.

Other important objects of the invention are to provide for automatic, self-tensioning of a cutter relatively to its guard, to provide' flexible' coupling of the cutter with its driving shaft, to provide` a flexible cutter to freely accommodate .itself to theguard, to provide an extended cutting surface between the cutter and the teeth of the guard and to provideu a self-clearingy cutter construction whereby the cut .material is expelled from the guard.

In accomplishing these and other objects of the invention, I have provided improved details of 0 structure, the preferred forms of which are illustrated in the accompanying drawing, wherein:

Fi'g. v1 is a perspective view of a shearing device constructed in accordance with my invention.

Fig. 2 is a similar view showing the parts of the Y shearing device in disassembled spaced relation to better illustrate their construction.

Fig. 3l is an enlarged, longitudinal, section through the device.

-4 is an enlarged cross-sectional view 30 throughguard and cutter on the line 4 4, Fig..3.

I designates anelectric motor, preferably of by which the shearing device may be readily manipulated, as later described. In the illustrated instance, the motor includes a cylindrical housing 2 enclosing the motor mechanismindicated by the armatureshaft 3 and a switch 4 for controlling current to the motor which is supplied from' an ordinary light socket through the'wires. The

end of the armature shaft 3 is tubularf-and'projects from the end of the in'otor housing to form r 'a base flange l provided with openings 3 through 5 5 as j PATENT oFFlcE '."aozaoff f f A, 'snnannvonnvicn- I l mie n nm'iaxmscuaml Applicationiune 1933,l SerialNm 676,507

Fig. 5 is an enlarged, perspectiveview of a fragsuitable shape and dimensions to form a handle l a drive connection for the cutter,l m-mirm Sie?? which screws 3 are extended to the brglet tothe end of the motor housing in axial alignment with'the shaft 3.-4 The bracket 6 also' includes a truncated cone-shaped neck portion In Vprovided with internal threads II to mount a bracket extension I2. f

. The extension I2 includes a cone-shaped body portion I3 having a reduced threaded shank' I4 forming an annular stop4 shoulder I5 with the i lbody portion. The outer end of the body' portion terminates in a cylindrical neck I6 having exter- 10 nal threads I1 for described.

The shank I4 o'f the bracket extension isA threadedly` engaged `in the threads vI'I of the bracket and the shoulder I5- thereof is drawn into l5 engagement with the endface I9 of the bracket to prevent rotation of the extension when the cutter is in operation.

The cutter. guard I8 includes a hollow truncated sleeve portion having `an intemally 20 threaded 'cylindrical base 2| mounted on the threaded neck I6 of the bracket extension and which is retained againstrotation thereon by a ring type lock nut 22 having internal threads 23 mounting the guard I8. later arranged for frictionally engaging the end face v25 of the guard, as clearlyshown in' Fig. 3. The outer periphery of "the llock nut is preferably knurled, asat 2 6, so that itinay be readily grasped i Y by the ngers and-moved into tight relation with the end of the guard after adjustment thereof relatively to the cutter, as later described.

The forward portion 20 iof the guard is provided with a4 cone shaped bo're 21 in which is ro- Y tatably mounted the cutter 28 and which has a 35 I Fig. 7 is a cross-sectional view throughanother terial cut by theshearlng device.

series ofopenings 29 -to forx'n outlets for the ma- 1 The conical portion of the guard is provided on the side opposite. the openings 29 with a series teeth 3I extendin'gln angular relation tothe axis of the guard to form angular-cutting faces v32 on 'the side edge thereof in the direction of the motor to. cooperate with the blade 'of the cuttei to provide a shearing cut', as laterdescribed; The 45 side ofthe guard carrying-the teeth is preferably reduced in thickness at the center of the teeth, as at33, and the ends of the teeth are of increased thickness toward their base,` as at 34 and $5 where they join thebody or back portion 36 50 of the guard, as clearly iiiustrated in` Fig. 4g vFormed onthe surface ,of the 4guard-at opposite sides of the thinnest portion of the teeth are spaced longitudinal ribs `or combs"4 31 and 33 fom Supports forengaging the .surfaceover 'for receiving the threads I1 and having its end 24 25 of annularly arranged slots 30 forming spaced 40 which the shearing device is moved, as later described. to comb the cut material into cutting relation with the teeth and to gauge the degree of cut afforded by the cutter. In the case of a razor. the combs also permit the skinl to cup upwardly therebetween so that a close shave is afforded.

'I'he cutter 29 includes a conical spiral ribbon 39 conforming in diameter and taper to the inner conical bore of .the guard, so that the outer peripheries 40 of the spiral move in sliding contact with the inner face 4I'of the guard teeth` and across the cutting edges 32 upon rotation of the spiral. The base 42 of the spiral terminates in a series of closely wound coils 43 having -internal threads 44 by which the cutter is mount- "ed on a flexible drive member 46, as now to be described.

The drive member 46 includes a exible shaft 2o portion 41 extending through an axial bore 48 in the bracket extension I2 and has its inner end provided with a. slotted coupling member 49 re.`

ceived within the tubular end of the armature shaft 3. The slot in the coupling engages a pin 25 50 having its ends mounted in the opposite walls of the 4shaft to provide a driving connection between the armature and the flexible portion of the driving member.

The opposite end of the driving shaft carries a threaded head 52 fixed securely thereon and having external threads 53 for engaging the threads 44 of the cutter and having an annular collar or shoulder portion 54 for tightly engaging the end face of the rst of the coils 43 so that when the cutter is threaded on the head, the

ange 54 thereof will prevent rotation of the cutter independently of the rotation of the shaft.

In order to prevent longitudinal movement of ,the cutter and its drive shaft relatively to the motor, the flexible portion of the drive shaft is provided with a sleeve 55 fixed thereto at a point within an enlarged portion 56 of the bore 48.

The sleeve 55 carries an annular flange 51 of suitable\diameter to be received in the enlarged portion of the bore to be anchored between spaced anti-friction bearing sets 58 and 59 having their opposite sides respectively engaging the end 60 of an enlarged portion of the bore and a washer 6| slidable on the sleeve at the end adjacent the motor. l

'I'he washer 6I is retained snugly against the bearing set 54 and the bearing set`58 against' the shoulder 60 by a coil spring 62 coiled about the exible portion of the shaft and having one end bearing against the washer 6i and its oppo-l site end against the sleeve 63 threaded in the end of the bore for adjusting tension of the Spring- It is thus apparent that when the bearing sets 58 and 59 are in position and retained by the spring and threaded sleeve 63, the driving member is prevented from movement in either direction relatively to the bracket extension. The spiral cutter will, therefore, be retained in xed relation relatively to the guard 2U to maintain the'desired contact between the .cutter and the inner surface of the guard.

In order to enhance the cutting properties of the spiral cutter, the innerface thereof is preferably provided with a series of V-shaped teeth or ribs 64 which cooperate with the periphery of the spiral to form a series of serrated teeth 65 along the cutting edge thereof.l 'I'he trailing portion of the spiral ribbon is preferably reduced in di- 475 ameter from substantially the center thereof, as

indicated at 68, so that only a narrow portion 61 is in contact with the guard. This is an important feature for the reason that as the ribbon wears relatively to the guard, the teeth 65 will retain their shape due to the fact that wear has 5 no effect other than shortening the length of the ribs 64. f

In order to prevent cut material from being emitted through the end of the guard the opening therein is closed by a suitable cap 69 having 10 a rounded portion to prevent injury to the surface being sheared by the sharp terminal edge of the guard.

In Fig. 6 is illustrated a modied form of the invention, wherein the toothed edge 68 of the 15 spiral cooperates with a cutting edge 10 on the guard 1| so that the material cut by the guard is not only cut along the sides of the teeth, as in the preferred form, but against the ends of the cutting edge 10 as well. 20

The form of cutter illustrated in Fig. 7 is substantially the sameas that illustrated in Fig. 6, except that the teeth extend at right angles to the axis of the cutterand the. guard is provided with a slot 12 for accommodating the hair or 25 material to be cut.

Since the guards shown in Figs. 6 and 7 operate against cutting edges 10, it is necessary to provide only one rib or comb 31 for gauging the amount of cut of the shearing device. 30

In using the preferred form of the device` constructed and assembled as described, tlreguard is moved angularly back and forth across' the surface being sheared in the direction of the teeth, so that the ribs act as a comb and the hair. 35 enters between the teeth to be sheared off by the spiral cutter as the nights thereof move across vthe cutting edges of the teeth.

When cut, the hairs are expelled through the openingsv 29 spirals.

To tighten the shearing tension of the cutter relatively to the guard, the ring 22 is loosened by slackening it from the end of the guard.

The guard is then moved retractively toward 45 the direction of the motor to cause the cutter to enter farther into the conical bore of the guard. 'Ihe spiral form of the'cutter provides4 suiicient inherent tension to retain the -teeth thereof in ,proper cutting relation with the. teeth of the 50.

guard. When the proper adjustment is made, the ring 22 is retightened against the guard Ato prevent rotation thereof on the bracket extension. Owing to the ribs or combs 31 and 33, a very close cut is aorded because pressure of the 55 guard against the surface being sheared presses the surface upwardly therebetweenin close contact with the cutting edge of the'cutter'.'

'Ihe forms of the invention illustrated in Figs. 6 and 7 are used in like manner except that they 60 .are moved in a single direction across the surface being sheared since they cut only against the cutting edges 1U.

' What I claim and desire to secure by Letters Patent is: A, f

1. In a device of thecharacter described. a guard support, a toothed guard on the support. a cutter including a flexible helical ribbon rotatable within the guard and having teeth cooperating with the teeth of the guard. and means ro- 70 tatably mounted in the guard support for rotating the cutter.

2. In a device of the character described, a support, a tapered tubular guard adjustably mounted on the support having angularly arranged by the propelling action of the 4u teeth, a helical ribbon-like cutter a series oi' closely wound coils terminating in nights rotatable within the guard about the axis of said the support and having a series of spaced slots forming teeth, a helical ribbon-like cutter having a series of closely wound coils lterminating in nights rotatable within the guard about the axis of said nights and in shearing contact with said teeth, a head mounting said closely wound coils of the cutter, means mounting the head in the guard support. and means for rotating the head.

4. In a device of the character described, a guard support, a guard mounted on the support and having a series of spaced slots to form teeth, a helical ribbon-like cutter having a series of closely wound coils terminating in nights rotatable within the guard about the axis of said nights and in shearing contact with said teeth, a head mounting said closely wound coils of the cutter. means mounting the head in the guard support, and means for rotating the head.

5. In a device of the character described, a support, a guard nxed on the support, a cutter rotatably mounted in the guard including a singie nxible ribbon coiled to form a helical cutting edge having free movement laterally from the longitudinal axis of said cutter whereby the helical cutting edge is maintained in cooperative cutting contact with the guard, and means connected with the support for rotating the cutter.

6. In a device of the character described, a support, a tapered tubular guard nxed to the support and having teeth, a cutter rotatably mounted in the guard including a single nexible ribbon coiled to form a helical cutting edge having i'ree movement laterally from the longitudinal axis of said cutter whereby the helial cutting edge is maintained in cooperative cuttingeontact with the teeth of the guard, and means connected with the support for rotating the cutter.

,7. In a device of the character described, a

support, a toothed tubular guard nxed on the A y support, a cutter rotatably mounted on the guard Yincluding a single nexible ribbon coiled to form a helical cutting edge having free movement laterally relatively to the longitudinal axis o! said cutter, whereby the helical cutting edge is maintained in cooperative cutting contact with the 5 guard, means for regulating said cutting contact, the means connected to the support for rotating the cutter.

8. In a device of the character described, a

support, a tubular guard member nxed on the 10 support, a cutter member rotatably mounted in" the guard including a single nexible ribbon coiled to form a helical cutting edge having cooperative cutting contact with the guard, means for ad- Justing one o! said members relatively to the l5 other to vary pressure of said contact, and means connected with the support for rotating the cutter member.

9. In a device ot the character described, a support, a tapered tubular guard adjustably mount- 2ov cai ribbon forming a nexible'cutter having nights rotatable within the guard about the axis of said 35v nights and retained in shearing contact with said teeth incidental to nexibility of the cutter, and ilexible means mounting the cutter for bearing support in the guard.

l1. In a device of the character described, a 40 support, a tubular guard nxed on the support and